The position of US ambassador to Ireland has been open since the resignation of Dan Rooney in December 2012.

There has been 30 ambassadors to Ireland and this is the longest period without one since 1927.

The ambassador's residence is next door to Áras an Uachtaráin in Dublin's Phoenix Park.

U.S. Secretary of State Hillary Clinton and former U.S. President Bill Clinton (Image: Pool/Getty Images)

Former US president Bill Clinton was rumoured as a replacement after visiting the country three times in a year.

His wife Hilary Clinton has dismissed the possibility by saying: "I would think my husband will be here (Ireland) many times in the future doing the work he's been doing without having to have the title of Ambassador."

Ireland, along with Belarus, Bolivia, Cosmoros, Lesotho and Romania are the other countries that don't have a US ambassador at the moment.